I think this is a new bug that’s cropped up recently. Fonts used to work fine but over the past few weeks I’ve noticed a few mentions of web fonts not loading. I don’t know if it’s something at googles end but I’m looking into it, but it’s just tricky to replicate consistently.

One thing to try is, when you open the project if the fonts don’t load, close the main window (back to start screen) then open proj up again, that usually works.